A Theoretical Study on the Effect of Residual Stress on Creep Brittle Crack Growth

Abstract

In this paper a theoretical analysis is presented for the interaction of combined mechanical and residual stresses in a brittle creeping material. At long times it is assumed that the residual stresses have completely redistributed and the near crack tip stress field is governed by C* for mechanical loading alone. At short times the near tip stress field is similar to the Riedel and Rice solution, but a new analysis is given that examines the relaxation of the combined stresses to provide expressions for the crack tip field parameter C[t]. It is assumed that with the introduction of residual stress the redistribution time from the initial elastic to the creep state remains largely unchanged. The subsequent result leads to faster local relaxation rates than for mechanical loading alone. The influence of residual stresses on the rate of creep crack growth in welded steel and sintered ceramic components are assessed by combining the new expressions for C[t] with experimentally determined growth rate laws.